Substrate Processing Apparatus and Method of Manufacturing Semiconductor Device

ABSTRACT

Described herein is a technique capable of improving a film uniformity on a surface of a substrate and a film uniformity among a plurality of substrates including the substrate. According to one aspect thereof, there is provided a substrate processing apparatus including: a substrate retainer including: a product wafer support region, an upper dummy wafer support region and a lower dummy wafer support region; a process chamber in which the substrate retainer is accommodated; a first, a second and a third gas supplier; and an exhaust system. Each of the first gas and the third gas supplier includes a vertically extending nozzle with holes, wherein an upper of an uppermost hole and a lower end of a lowermost hole are arranged corresponding to an uppermost and a lowermost dummy wafer, respectively. The second gas supplier includes a nozzle with holes or a slit.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.17/017,147 filed Sep. 10, 2020, which is a continuation of InternationalApplication No. PCT/JP2018/011625, filed on Mar. 23, 2018, the entirecontents of which are hereby incorporated by reference.

TECHNICAL FIELD

The present disclosure relates to a substrate processing apparatus and amethod of manufacturing a semiconductor device.

BACKGROUND

As a part of manufacturing processes of a semiconductor device, aprocess of forming a film on a substrate using a plurality of nozzlesmay be performed.

SUMMARY

Described herein is a technique capable of improving a uniformity of afilm on a surface of a substrate and a uniformity of the film among aplurality of substrates.

According to one aspect of the technique of the present disclosure,there is provided a processing apparatus including: a substrate retainerincluding: a product wafer support region where a plurality of productwafers with a pattern formed thereon are arranged and supported; anupper dummy wafer support region provided above the product wafersupport region and capable of supporting a plurality of dummy wafers;and a lower dummy wafer support region provided below the product wafersupport region and capable of supporting a plurality of dummy wafers; aprocess chamber in which the substrate retainer is accommodated; a firstgas supplier, a second gas supplier and a third gas supplier configuredto supply gases into the process chamber; and an exhaust systemconfigured to exhaust an inner atmosphere of the process chamber,wherein each of the first gas supplier and the third gas supplierincludes a nozzle of a pipe shape extending in a vertical directionalong the substrate retainer, a plurality of gas supply holes beingprovided at each of the first gas supplier and the third gas supplier,wherein an upper end of an uppermost gas supply hole among the pluralityof the gas supply holes is arranged corresponding to an uppermost dummywafer among the plurality of the dummy wafers supported in the upperdummy wafer support region and a lower end of a lowermost gas supplyhole among the plurality of the gas supply holes is arrangedcorresponding to a lowermost dummy wafer among the plurality of thedummy wafers supported in the lower dummy wafer support region, whereinthe second gas supplier includes a nozzle extending in the verticaldirection along the substrate retainer and at which a gas supply port isprovided, and wherein the gas supply port is constituted by a pluralityof gas supply holes or by a slit-shaped opening.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 schematically illustrates a vertical cross-section of a verticaltype process furnace of a substrate processing apparatus preferably usedin an embodiment described herein.

FIG. 2 schematically illustrates a horizontal cross-section of a part ofthe vertical type process furnace of the substrate processing apparatuspreferably used in the embodiment described herein.

FIG. 3 is a block diagram schematically illustrating a configuration ofa controller and related components of the substrate processingapparatus preferably used in the embodiment described herein.

FIG. 4A schematically illustrates a horizontal cross-section of nozzlesand adjacent structures thereof according to the embodiment describedherein, and FIG. 4B schematically illustrates a positional relationshipbetween the nozzles according to the embodiment described herein and asubstrate accommodated in a substrate retainer.

FIG. 5A schematically illustrates a horizontal cross-section of nozzlesand periphery thereof according to a first modified example describedherein, and FIG. 5B schematically illustrates a positional relationshipbetween the nozzles according to the first modified example describedherein and the substrate accommodated in the substrate retainer.

FIG. 6A schematically illustrates a horizontal cross-section of nozzlesand periphery thereof according to a second modified example describedherein, and FIG. 6B schematically illustrates a positional relationshipbetween the nozzles according to the second modified example describedherein and the substrate accommodated in the substrate retainer.

FIG. 7A schematically illustrates a horizontal cross-section of nozzlesand periphery thereof according to a third modified example describedherein, and FIG. 7B schematically illustrates a positional relationshipbetween the nozzles according to the third modified example describedherein and the substrate accommodated in the substrate retainer.

FIG. 8A schematically illustrates a positional relationship betweennozzles according to a comparative example described herein and thesubstrate accommodated in the substrate retainer, and FIG. 8Bschematically illustrates a positional relationship between the nozzlesaccording to an example of the embodiment described herein and thesubstrate accommodated in the substrate retainer.

FIG. 9A schematically illustrates a simulation result showing aconcentration distribution of a silicon source in the vertical typeprocess furnace when the nozzles according to the comparative exampleshown in FIG. 8A are used, and FIG. 9B schematically illustrates athickness distribution of a film on a surface of a product wafer and athickness distribution of the film among a plurality of product wafersshown in FIG. 9A.

FIG. 10A schematically illustrates a simulation result showing aconcentration distribution of a silicon source in the vertical typeprocess furnace when the nozzles according to the example of theembodiment shown in FIG. 8B are used, and FIG. 10B schematicallyillustrates a thickness distribution of the film on the surface of theproduct wafer and a thickness distribution of the film among theplurality of the product wafers shown in FIG. 10A.

FIG. 11 schematically illustrates evaluation results of thicknessdistributions of the film on a surface of a substrate (“WiW”) when thefilm is formed using the nozzles according to the comparative exampleand the nozzles according to the example of the embodiment.

FIG. 12 schematically illustrates evaluation results of thicknessdistributions of the film among a plurality of substrates including thesubstrate (“WtW”) when the film is formed using the nozzles according tothe comparative example and the nozzles according to the example of theembodiment.

FIG. 13 is a flow chart schematically illustrating a substrateprocessing of forming the film on the substrate using the substrateprocessing apparatus preferably used in the embodiment described herein.

FIG. 14 schematically illustrates a vertical cross-section of a verticaltype process furnace of a substrate processing apparatus according to afourth modified example described herein.

DETAILED DESCRIPTION Embodiment of Present Disclosure

Hereinafter, an embodiment according to the technique of the presentdisclosure will be described with reference to FIGS. 1 through 4. Asubstrate processing apparatus according to the embodiment of thetechnique is configured as an example of a semiconductor manufacturingapparatus used for manufacturing a semiconductor device.

(1) Configuration of Substrate Processing Apparatus

As shown in FIG. 1, a process furnace 202 of the substrate processingapparatus according to the present embodiment includes a heater 207serving as a heating apparatus (heating structure). The heater 207 is ofa cylindrical shape, and is vertically installed while being supportedby a heater base (not shown) serving as a support plate. The heater 207also functions as an activator (exciter) capable of activating(exciting) a process gas by heat.

A reaction tube 203 is provided in an inner side of the heater 207 so asto be coaxially aligned with the heater 207. A reaction vessel (which isa process vessel) is constituted by the reaction tube 203. For example,the reaction tube 203 is made of a heat resistant material such asquartz (SiO2) and silicon carbide (SiC). The reaction tube 203 is of acylindrical shape with an open lower end and a closed upper end. Theupper end of the reaction tube 203 is closed by a flat wall body. Thatis, the reaction tube 203 includes a ceiling. A cylindrical portion 209of a cylindrical shape is provided at a side wall of the reaction tube203. A gas supply area (buffer) 222 and a gas exhaust area 224 areprovided on an outer wall of the cylindrical portion 209. A processchamber 201 is provided in the cylindrical portion 209 of the reactiontube 203. A plurality of wafers including a wafer 200 serving as asubstrate is processed in the process chamber 201 under a hightemperature and a reduced pressure. The process chamber 201 isconfigured to accommodate a boat 217 serving as a substrate retainercapable of accommodating (supporting or holding) the plurality of thewafers including the wafer 200 vertically arranged in a horizontalorientation in a multistage manner.

The gas supply area 222 is configured to protrude outward from asidewall of the cylindrical portion 209 of the reaction tube 203. Anouter wall of the gas supply area 222 is connected to the outer wall ofcylindrical portion 209, and is provided concentrically with thecylindrical portion 209. A diameter of the gas supply area 222 isgreater than an outer diameter of the cylindrical portion 209. A lowerend of the gas supply area 222 is open, and an upper end of the gassupply area 222 is closed by a flat wall body. Nozzles 304 a, 304 b and304 c which will be described later are accommodated in the gas supplyarea 222 along a longitudinal direction (that is, the verticaldirection) of the gas supply area 222. A partition wall 252, whichserves as a part of the sidewall of the cylindrical portion 209,constitutes a boundary between the gas supply area 222 and thecylindrical portion 209. Gas supply slits 235 are opened on thepartition wall 252, and are configured to communicate (connect) withinsides of the gas supply area 222 and the process chamber 201. The gassupply slits 235 may be arranged in a grid pattern including a pluralityof rows and a plurality of columns. Preferably, three columns of the gassupply slits 235 are arranged in a circumferential direction of the gassupply area 222 so as to allow each region of the gas supply area 222 toseparately communicate with the process chamber 201, and a plurality ofrows of the gas supply slits 235, each of which includes three of thegas supply slits 235, are arranged in a manner respectivelycorresponding to the surfaces (upper surfaces) of the plurality of thewafers including the wafer 200 such that the number of the rows is equalto the number of the wafers counted along the longitudinal direction ofthe gas supply area 222.

The gas exhaust area 224 protrudes outward from a sidewall of thecylindrical portion 209 facing the sidewall where the gas supply area222 is provided. The plurality of the wafers including the wafer 200 areaccommodated in the process chamber 201 between the gas supply area 222and the gas exhaust area 224. An outer wall of the gas exhaust area 224is connected to the outer wall of the cylindrical portion 209, and isaligned along a circle which shares its center with the cylindricalportion 209 and whose outer diameter is greater than that of thecylindrical portion 209. A lower end and an upper end of the gas exhaustarea 224 are closed by flat wall bodies, respectively.

Gas exhaust slits 236 described later are provided on a partition wall254 which is a wall body constituting a boundary between the gas exhaustarea 224 and the cylindrical portion 209. The partition wall 254 servesas a part of the cylindrical portion 209, and a part of an outer surfaceof the partition wall 254 constitutes a side surface facing the gasexhaust area 224. Thereby, the reaction tube 203 includes a double tubestructure where the gas supply area 222 and the gas exhaust area 224 areprovided.

The lower end of the reaction tube 203 is supported by a manifold 226 ofa cylindrical shape. For example, the manifold 226 is made of a metalsuch as nickel alloy and stainless steel, or is made of a heat resistantmaterial such as quartz (SiO₂) and silicon carbide (SiC). A flange (notshown) is provided at an upper end of the manifold 226, and the lowerend of the reaction tube 203 is provided on the flange and supported bythe flange. A seal 220 a such as an O-ring is provided between theflange and the upper end of the reaction tube 203 to airtightly seal aninside of the reaction tube 203.

A seal cap 219 is airtightly attached to a lower end opening of themanifold 226 via a seal 220 b such as an O-ring. The seal cap 219 isconfigured to airtightly seal a lower end opening of the reaction tube203, that is, the lower end opening of the manifold 226. For example,the seal cap 219 is made of a metal such as nickel alloy and stainlesssteel, and is of a disk shape. The seal cap 219 may be configured suchthat an inner surface of the seal cap 219 is covered with a heatresistant material such as quartz (SiO₂) and silicon carbide (SiC).

A boat support 218 configured to support the boat 217 is provided on theseal cap 219. The boat support 218 is made of a heat resistant materialsuch as quartz and SiC. The boat support 218 functions not only as asupport capable of supporting the boat 217 but also as a heat insulator.The boat 217 is provided vertically on the boat support 218. Forexample, the boat 217 is made of a heat resistant material such asquartz and SiC. The boat 217 includes a bottom plate that can be placedon the boat support 218 and a top plate provided above the bottom plate.A plurality of support columns are provided between the bottom plate andthe top plate. The plurality of the support columns are installed toconnect the bottom plate and the top plate. The boat 217 accommodates(supports) the plurality of the wafers including the wafer 200. Theplurality of the wafers is horizontally oriented with predeterminedintervals therebetween. That is, the plurality of the wafers issupported by the plurality of the support columns of the boat 217 withtheir centers aligned with each other. A stacking direction of theplurality of the wafers is equal to an axial direction of the reactiontube 203.

A boat rotator 267 configured to rotate the boat 217 is provided at theseal cap 219 opposite to the process chamber 201. A rotating shaft 265of the boat rotator 267 is connected to the boat support 218 through theseal cap 219. As the boat rotator 267 rotates the boat 217 via the boatsupport 218, the plurality of the wafers including the wafer 200supported by the boat 217 are rotated.

The seal cap 219 may be elevated or lowered in the vertical direction bya boat elevator 115 provided outside the reaction tube 203. The boatelevator 115 serves as an elevator. As the seal cap 219 is elevated orlowered in the vertical direction by the boat elevator 115, the boat 217is transferred (loaded) into the process chamber 201 or transferred(unloaded) out of the process chamber 201.

Nozzle supports 350, which are configured to support the nozzles (whichare injectors) 304 a, 304 b and 304 c, respectively, are installed atthe manifold 226 so as to pass through the manifold 226. The nozzlesupports 350 are bent in an L shape. According to the presentembodiment, for example, three nozzle supports are installed as thenozzle supports 350. For example, the nozzle supports 350 are made of amaterial such as nickel alloy and stainless steel. Gas supply pipes 310a, 310 b and 310 c configured to supply gases such as the process gasinto the process chamber 201 are connected to first ends of the nozzlesupports 350, respectively. The nozzles 304 a, 304 b and 304 c areconnected to second ends of the nozzle supports 350, respectively. Forexample, the nozzles 304 a, 304 b and 304 c of a pipe shape are made ofa heat resistant material such as quartz and SiC.

As shown in FIG. 2, inner walls 248 and inner walls 250 are providedinside the gas supply area 222 and the gas exhaust area 224,respectively, so as to divide (partition) inner spaces of each of thegas supply area 222 and the gas exhaust area 224 into a plurality ofspaces. The gas supply area 222, the inner walls 248 and the inner walls250 are made of the same material as the reaction tube 203, for example,a heat resistant material such as quartz or SiC. According to thepresent embodiment, for example, two inner walls are provided as theinner walls 248 and two inner walls are provided as the inner walls 250.Thus, the inner space of each of the gas supply area 222 and the gasexhaust area 224 is divided into three spaces.

The two inner walls 248 are provided so as to divide (partition) theinner space of the gas supply area 222 from a lower end to an upper endthereof into a plurality of spaces. As a result, for example, the threespaces separated by the two inner walls 248 are provided. The nozzles304 a, 304 b and 304 c are provided in the plurality of the spaces,respectively. Thus, it is possible to suppress the process gas suppliedthrough the nozzles 304 a, 304 b and 304 c from mixing with one anotherin the gas supply area 222. With the configuration of the gas supplyarea 222 described above, it is possible to suppress the formation of afilm or the generation of by-products in the gas supply area 222 due tothe mixing of the process gas in the gas supply area 222. Preferably,the inner walls 248 are provided so as to divide the gas supply area 222from the lower end to the upper end thereof such that the three spacesseparated from one another are provided.

Similar to the inner walls 248, the two inner walls 250 are provided soas to divide (partition) the inner space of the gas exhaust area 224into a plurality of spaces. Preferably, the inner walls 250 are providedso as to divide the gas exhaust area 224 from the vicinity of an upperend thereof to the vicinity of an exhaust port 230 described later.Preferably, when an outer diameter of the outer wall of the gas supplyarea 222 is the same as the an outer diameter of an outer wall of thegas exhaust area 224, it is possible to suppress the distortion of thereaction tube 203 and to reduce a dead space between the heater 207 andthe reaction tube 203. For the same reason, it is preferable that across-sectional area of a flow path of the gas in the gas supply area222 is the same as a cross-sectional area of a flow path of the gas inthe gas exhaust area 224. In addition, preferably, a cross-sectionalarea of the flow path of the gas in each space in the gas supply area222 is the same as a cross-sectional area of the flow path of the gas ineach space in the gas exhaust area 224 facing each space in the gassupply area 222. In addition, preferably, the gas exhaust slits 236 areprovided similar to the gas supply slits 235.

A source (source gas) containing a predetermined element (main element)constituting a film is supplied into the process chamber 201 from a gassupply source 360 b serving as a second gas supply source through thegas supply pipe 310 b provided with an MFC 320 b and a valve 330 b andthe nozzle 304 b. For example, a halosilane-based gas containing silicon(Si) as the predetermined element and a halogen element may be suppliedinto the process chamber 201 as the source gas. The source gas refers toa thermally decomposable source gas and a source in a gaseous state. Forexample, the source gas may refer to the source in the gaseous stateunder a normal temperature and a normal pressure (atmospheric pressure)or a gas obtained by vaporizing a source in a liquid state under thenormal temperature and the normal pressure. Halosilane refers to silanecontaining a halogen group. That is, the halogen group includes ahalogen element such as chlorine (Cl), fluorine (F), bromine (Br) andiodine (I). As the halosilane-based gas, for example, a source gascontaining silicon (Si) and chlorine, that is, a chlorosilane-based gasmay be used. The chlorosilane-based gas serves as a silicon source. Asthe chlorosilane-based gas, for example, hexachlorodisilane (Si₂Cl₆,abbreviated as HCDS) gas may be used.

A reactant whose chemical structure (molecular structure) is differentfrom that of the source gas is supplied into the process chamber 201from a gas supply source 360 a serving as a first gas supply sourcethrough the gas supply pipe 310 a provided with an MFC 320 a and a valve330 a and the nozzle 304 a. The reactant (also referred to as a“reactive gas”) is more difficult to be thermally decomposed or to beactivated than the source gas. For example, a hydrogen nitride-basedgas, which is a nitriding gas serving as a nitrogen-containing gas, issupplied into the process chamber 201 as the reactant. The hydrogennitride-based gas serves as a nitrogen (N) source. As the hydrogennitride-based gas, for example, ammonia (NH₃) gas may be used. Thereactant may also be supplied into the process chamber 201 from a gassupply source 360 cserving as a third gas supply source through the gassupply pipe 310 c provided with an MFC 320 c and a valve 330 c and thenozzle 304 c.

An inert gas such as nitrogen gas (N₂ gas) is supplied into the processchamber 201 from a gas supply source 360 d, a gas supply source 360 eand a gas supply source 360 f through gas supply pipes 310 d through 310f provided with MFCs 320 d through 320 f and valves 330 d through 330 f,respectively, the gas supply pipes 310 a through 310 c and the nozzles304 a, 304 b and 304 c. The N₂ gas serves as a purge gas, a carrier gasor a dilution gas. In addition, the N₂ gas also serves as a control gaswhich controls a thickness distribution of the film formed on thesurface of the wafer 200.

A first process gas supply system (also referred to as a “first gassupply system”) serving as a reactant supply system is constitutedmainly by the gas supply pipe 310 a, the MFC 320 a, the valve 330 a andthe nozzle 304 a. The first process gas supply system may furtherinclude the gas supply source 360 a. A second process gas supply system(also referred to as a “second gas supply system”) serving as a sourcesupply system is constituted mainly by the gas supply pipe 310 b, theMFC 320 b, the valve 330 b and the nozzle 304 b. The second process gassupply system may further include the gas supply source 360 b. A thirdprocess gas supply system (also referred to as a “third gas supplysystem”) serving as a reactant supply system is constituted mainly bythe gas supply pipe 310 c, the MFC 320 c, the valve 330 c and the nozzle304 c. The third process gas supply system may further include the gassupply source 360 c. An inert gas supply system is constituted mainly bythe gas supply pipes 310 a through 310 f, the MFCs 320 d through 320 f,the valves 330 d through 330 f and the nozzles 304 a, 304 b and 304 c.The inert gas supply system may further include the gas supply sources360 d through 360 f.

The exhaust port 230 is provided below the gas exhaust area 224. Anexhaust pipe 231 is connected to the exhaust port 230. A vacuum pump 246serving as a vacuum exhauster is connected to the exhaust pipe 231through a pressure sensor 245 and an APC (Automatic Pressure Controller)valve 244. The pressure sensor 245 serves as a pressure detector(pressure meter) to detect an inner pressure of the process chamber 201,and the APC valve 244 serves as a pressure controller (pressureregulator). The vacuum pump 246 is configured to vacuum-exhaust an inneratmosphere of the process chamber 201 such that the inner pressure ofthe process chamber 201 reaches a predetermined pressure (vacuumdegree). The exhaust pipe 231 at a downstream side of the vacuum pump246 is connected to a component such as a waste gas processing apparatus(not shown). The APC valve 244 serves as an opening/closing valve. Withthe vacuum pump 246 in operation, the APC valve 244 may be opened orclosed to vacuum-exhaust the process chamber 201 or to stop the vacuumexhaust. With the vacuum pump 246 in operation, by adjusting an openingdegree of the APC valve 244, the APC valve 244 is configured to adjustthe inner pressure of the process chamber 201 by adjusting a conductancethereof. An exhaust system serving as an exhaust structure isconstituted mainly by the exhaust pipe 231, the APC valve 244 and thepressure sensor 245. The exhaust system may further include the vacuumpump 246.

A temperature sensor (not shown) serving as a temperature detector isprovided in the reaction tube 203. The electrical power supplied to theheater 207 is adjusted based on temperature information detected by thetemperature sensor such that a desired temperature distribution of aninner temperature of the process chamber 201 is obtained.

As shown in FIG. 3, a controller 280 serving as a control device(control structure) is constituted by a computer including a CPU(Central Processing Unit) 121 a, a RAM (Random Access Memory) 121 b, amemory 121 c and an I/O port 121 d. The RAM 121 b, the memory 121 c andthe I/O port 121 d may exchange data with the CPU 121 a through aninternal bus 121 e. For example, an input/output device 122 such as atouch panel is connected to the controller 280.

For example, the memory 121 c is configured by components such as aflash memory and HDD (Hard Disk Drive). A control program forcontrolling the operation of the substrate processing apparatus or aprocess recipe containing information on the sequences and conditions ofa substrate processing described later is readably stored in the memory121 c. The process recipe is obtained by combining steps of thesubstrate processing described later such that the controller 280 canexecute the steps to acquire a predetermine result, and functions as aprogram. Hereinafter, the process recipe and the control program areindividually or collectively referred to as a “program”. The processrecipe may also be referred to as a recipe. In the presentspecification, the term “program” may indicate only the process recipe,may indicate only the control program, or may indicate both of theprocess recipe and the control program. The RAM 121 b functions as amemory area (work area) where a program or data read by the CPU 121 a istemporarily stored.

The I/O port 121 d is connected to the above-described components suchas the MFCs 320 a through 320 f, the valves 330 a through 330 f, thepressure sensor 245, the APC valve 244, the vacuum pump 246, the heater207, the boat rotator 267 and the boat elevator 115.

The CPU 121 a is configured to read the control program from the memory121 c and execute the control program. In addition, the CPU 121 a isconfigured to read the process recipe from the memory 121 c according toan instruction such as an operation command inputted from theinput/output device 122. According to the contents of the process reciperead from the memory 121 c, the CPU 121 a may be configured to controlvarious operations such as flow rate adjusting operations for variousgases by the FCs 320 a through 320 f, opening/closing operations of thevalves 330 a through 330 f, an opening/closing operation of the APCvalve 244, a pressure adjusting operation by the APC valve 244 based onthe pressure sensor 245, a start and stop of the vacuum pump 246, atemperature adjusting operation of the heater 207 based on thetemperature sensor (not shown), an operation of adjusting rotation androtation speed of the boat 217 by the boat rotator 267 and an elevatingand lowering operation of the boat 217 by the boat elevator 115.

The controller 280 may be embodied by installing the above-describedprogram stored in an external memory 123 into a computer. For example,the external memory 123 may include a magnetic disk such as a hard diskdrive (HDD), an optical disk such as a CD, a magneto-optical disk suchas an MO, a semiconductor memory such as a USB memory. The memory 121 cor the external memory 123 may be embodied by a non-transitory computerreadable recording medium. Hereafter, the memory 121 c and the externalmemory 123 are individually or collectively referred to as recordingmedia. In the present specification, the term “recording media” mayindicate only the memory 121 c, may indicate only the external memory123, and may indicate both of the memory 121 c and the external memory123. Instead of the external memory 123, a communication means such asthe Internet and a dedicated line may be used for providing the programto the computer.

In the process furnace 202 described above, in a state where theplurality of the wafers including the wafer 200 to be batch-processedare stacked in the boat 217 in a multistage manner, the boat 217 isaccommodated in the process chamber 201 while being supported by theboat support 218, and the gases are supplied to the plurality of thewafers including the wafer 200 accommodated in the process chamber 201through the nozzles 304 a, 304 b and 304 c.

In recent years, the semiconductor device is three-dimensionalized inorder to increase the degree of integration thereof, so that a surfacearea of a wafer on which a semiconductor film is formed increases. Asthe surface area of the wafer increases, the consumption of afilm-forming gas such as the process gas increases, and a uniformity ofthe semiconductor film deposited on the wafer may deteriorate.

In general, in the vertical type process furnace of the substrateprocessing apparatus serving as an example of the semiconductormanufacturing apparatus, a plurality of dummy wafers are loaded on anupper portion and a lower portion of the boat 217 accommodating(holding) the plurality of the wafers including the wafer 200 in orderto uniformize the temperature of each of the plurality of the wafersarranged in a height direction (vertical direction). Thereby, the filmto be grown may be uniformized. However, since a dummy wafer is usuallya flat wafer, a surface area of the dummy wafer is different from asurface area of a product wafer on which a pattern is formed. Recently,the surface area of the product wafer may be 50 times or 100 times thatof the flat wafer, and the surface area of the product wafer isincreasing year by year. However, as the surface area increases, anamount of the consumption of the film-forming gas tends to increase.That is, an amount of the source gas consumed by the dummy wafer and theproduct wafer is different between a dummy wafer support region (whichis a region where the plurality of the dummy wafers are loaded) and aproduct wafer support region (which is a region where a plurality ofproduct wafers are loaded). Therefore, when the same amount of thesource gas is supplied to the plurality of the wafers stacked in theheight direction, the source gas is surplus in some location and thesource gas is insufficient in other location. Due to the difference in aconcentration of the source gas among the plurality of the wafers, itbecomes difficult to uniformize the film among the plurality of thewafers.

According to the present embodiment, to cope with the problems such asthe deterioration of the uniformity of the film quality and the filmthickness due to the increase in the surface area of the product wafer,it is possible to improve the uniformity of the film on the surface ofthe product wafer and the uniformity of the film among the plurality ofthe product wafers.

According to the present embodiment, the three nozzles 304 a, 304 b and304 c are provided in the gas supply area 222, and are configured tosupply two or more types of gas into the process chamber 201. Theprocess chamber 201 is of a cylindrical shape. An inner diameter of theprocess chamber 201 is 104% to 108% of a maximum diameter of the wafer200 that can be accommodated in the process chamber 201. The nozzles 304a, 304 b and 304 c are accommodated in the gas supply area 222 formed byprotruding a part of the process chamber 201 outward while separated(isolated) from one another. Configurations of the nozzles 304 a, 304 band 304 c configured to supply the two or more types of the gas into theprocess chamber 201 will be described with reference to FIGS. 4A and 4B.The nozzle 304 a, the nozzle 304 b, and the nozzle 304 c are used as afirst gas supplier, a second gas supplier and a third gas supplier,respectively.

FIG. 4A schematically illustrates a horizontal cross-section of thenozzles 304 a, 304 b and 304 c and periphery thereof in the productwafer support region where the plurality of the product wafers includinga product wafer 200 a (also simply referred to as “product wafers 200a”) in the gas supply area 222 is accommodated (held), and FIG. 4Bschematically illustrates a positional relationship between the nozzles304 a, 304 b and 304 c and the plurality of the wafers including thewafer 200 accommodated (stacked) in the boat 217 in a multistage manner.

The boat 217 includes: the product wafer support region where theproduct wafers 200 a are accommodated (supported) at regular intervals;an upper dummy wafer support region provided above the product wafersupport region and capable of supporting the plurality of the dummywafers including a dummy wafer 200 b (also simply referred to as “dummywafers 200 b”); and a lower dummy wafer support region provided belowthe product wafer support region and capable of supporting dummy wafers200 b. According to the present embodiment, the product wafer 200 arefers to a product wafer with a pattern formed thereon, and the dummywafer 200 b refers to a flat bare wafer with no pattern formed thereon,or refers to a wafer whose surface area is between that of the productwafer 200 a and that of the bare wafer. That is, one or more dummywafers are stacked and supported above and below the product wafers 200a, respectively. One or more monitor wafers (for example, three monitorwafers) may be supported in the product wafer support region among theproduct wafers 200 a. The number of the product wafers supported in theproduct wafer support region may be set to an integral multiple of thenumber (for example, 25) of wafers that can be accommodated in a wafercarrier such as a FOUP.

The nozzles 304 a, 304 b and 304 c are provided in the gas supply area222 from a lower portion toward an upper portion along the longitudinaldirection of the gas supply area 222 (vertical direction). That is, eachof the nozzles 304 a, 304 b and 304 c extends in the vertical directionalong the boat 217 accommodated in the process chamber 201, and isconfigured as a long nozzle of a straight tube (straight pipe) shape.

In addition, the nozzles 304 a, 304 b and 304 c are arranged in the gassupply area 222 in the vicinity of an outer periphery of the processchamber 201 sequentially in the order of the nozzle 304 a, the nozzle304 b, and the nozzle 304 c. That is, the nozzle 304 a and the nozzle304 c configured to supply the inert gas or the nitriding gas arearranged on both sides of the nozzle 304 b configured to supply thesource gas. That is, the nozzle 304 b configured to supply the sourcegas is arranged in the center, and the nozzle 304 a and the nozzle 304 cconfigured to supply the inert gas or the nitriding gas are arrangedsuch that the nozzle 304 b is interposed between the nozzle 304 a andthe nozzle 304 c.

The nozzle 304 a is connected to the gas supply pipe 310 a such that afluid can flow from the gas supply sources 360 a and 360 d to a lowerend of the nozzle 304 a through the gas supply pipe 310 a.

The nozzle 304 b is connected to the gas supply pipe 310 b such that afluid can flow from the gas supply sources 360 b and 360 e to a lowerend of the nozzle 304 b through the gas supply pipe 310 b.

The nozzle 304 c is connected to the gas supply pipe 310 c such that afluid can flow from the gas supply sources 360 c and 360 f to a lowerend of the nozzle 304 c through the gas supply pipe 310 c.

A plurality of gas supply holes (also simply referred to as “gas supplyholes”) 232 a and a plurality of gas supply holes (also simply referredto as “gas supply holes”) 232 c configured to supply the gas areprovided on side surfaces of the nozzle 304 a and the nozzle 304 c,respectively. Each of the gas supply holes 232 a and the gas supplyholes 232 c is a small circular hole of a pinhole shape. For example,each of the gas supply holes 232 a and the gas supply holes 232 c isconstituted by a plurality of openings or a plurality of verticallyelongated slits. An upper end of an uppermost gas supply hole among thegas supply holes 232 a of the nozzle 304 a and an upper end of anuppermost gas supply hole among the gas supply holes 232 c of the nozzle304 c are arranged corresponding to an uppermost dummy wafer among thedummy wafers 200 b supported in the upper dummy wafer support region. Inaddition, a lower end of a lowermost gas supply hole among the gassupply holes 232 a of the nozzle 304 a and a lower end of a lowermostgas supply hole among the gas supply holes 232 c of the nozzle 304 c arearranged corresponding to a lowermost dummy wafer among the dummy wafers200 b supported in the lower dummy wafer support region. That is, in thenozzle 304 a and the nozzle 304 c, the gas supply holes 232 a and thegas supply holes 232 c are provided in the upper dummy wafer supportregion, the product wafer support region and the lower dummy wafersupport region. Preferably, the gas supply holes 232 a and the gassupply holes 232 c are provided at predetermined intervals so as tocorrespond to the surfaces (upper surfaces) of the plurality of thewafers including the dummy wafer 200 b or correspond to the openings ofthe gas supply slits 235.

A plurality of gas supply holes (also simply referred to as “gas supplyholes”) 232 b serving as a gas supply port configured to supply the gasare provided on a side surface of the nozzle 304 b. An upper end of anuppermost gas supply hole among the gas supply holes 232 b of the nozzle304 b is arranged lower than a lowermost dummy wafer among the dummywafers 200 b supported in the upper dummy wafer support region. Inaddition, a lower end of a lowermost gas supply hole among the gassupply holes 232 b of the nozzle 304 b is arranged higher than anuppermost dummy wafer among the dummy wafers 200 b supported in thelower dummy wafer support region. That is, on the side surface of thenozzle 304 b, the gas supply holes 232 b are provided in the productwafer support region, but are not provided in the upper dummy wafersupport region and the lower dummy wafer support region. The number ofthe gas supply holes 232 b is equal to the number of the product wafers200 a, and the gas supply holes 232 b are configured to discharge(eject) the source gas toward each surface (upper surface) of theproduct wafers.

The gas supply holes 232 a, the gas supply holes 232 b and the gassupply holes 232 c are opened so as to face a center of the reactiontube 203.

(2) Substrate Processing

Hereinafter, an exemplary sequence (film-forming sequence) of thesubstrate processing (film-forming process) of forming a film on thewafer 200 serving as a substrate, which is a part of manufacturingprocesses of a semiconductor device, will be described. The exemplarysequence is performed by using the above-described substrate processingapparatus. Hereinafter, the operations of the components of thesubstrate processing apparatus are controlled by the controller 280.

The substrate processing will be described by way of an example in whicha silicon nitride film (Si3N4 film) is formed on the product wafer 200 aserving as the wafer 200 by supplying the silicon source gas (sourcegas) and the nitriding gas in accordance with the following film-formingsequence with reference to FIG. 13. For example, a pattern whose surfacearea is large and at which a concave-convex structure is formed isprovided on a surface of the product wafer 200 a. The boat 217 may alsobe loaded with the dummy wafers 200 b as shown in FIG. 4, and the dummywafer 200 b may be processed together with the product wafer 200 a.However, hereinafter, the description of the wafer 200 mainly refers tothe product wafer 200 a.

In the present specification, the term “wafer” may refer to “a waferitself” or may refer to “a wafer and a stacked structure (aggregatedstructure) of a predetermined layer (or layers) or a film (or films)formed on a surface of the wafer”. In the present specification, theterm “a surface of a wafer” may refer to “a surface of a wafer itself”or may refer to “a surface of a predetermined layer or a film formed ona wafer”. Thus, in the present specification, “forming a predeterminedlayer (or film) on a wafer” may refer to “forming a predetermined layer(or film) on a surface of a wafer itself” or may refer to “forming apredetermined layer (or film) on a surface of another layer or anotherfilm formed on a wafer”. In the present specification, the term“substrate” and “wafer” may be used as substantially the same meaning.That is, the term “substrate” may be substituted by “wafer” and viceversa.

Wafer Charging and Boat Loading Step S901

The plurality of the wafers including the wafer 200 are charged(transferred) into the boat 217 (wafer charging step). After the boat217 is charged with the plurality of the wafers, the lower end openingof the manifold 226 is opened. Then, as shown in FIG. 1, the boat 217charged with the plurality of the wafers is elevated by the boatelevator 115 and loaded (transferred) into the process chamber 201 (boatloading step). With the boat 217 loaded, the seal cap 219 seals thelower end opening of the manifold 226 via the O-ring 220 b.

Pressure Adjusting Step S902

The vacuum pump 246 vacuum-exhausts the inner atmosphere of the processchamber 201 until the inner pressure of the process chamber 201 in whichthe plurality of the wafers including the wafer 200 are accommodatedreaches a desired pressure (vacuum degree). In the pressure adjustingstep S902, the inner pressure of the process chamber 201 is measured bythe pressure sensor 245, and the APC valve 244 is feedback-controlledbased on measured pressure information.

Temperature Adjusting Step S903

The heater 207 heats the process chamber 201 until the temperature ofthe wafer 200 in the process chamber 201 reaches a desired film-formingtemperature. The state of electric conduction to the heater 207 isfeedback-controlled based on the temperature information detected by atemperature sensor 263 such that the desired temperature distribution ofthe inner temperature of the process chamber 201 is obtained. The boatrotator 267 rotates the plurality of the wafers including the wafer 200by rotating the boat 217. The vacuum pump 246 continuouslyvacuum-exhausts the inner atmosphere of the process chamber 201, theheater continuously heats the process chamber 201 and the boat rotator267 continuously rotates the plurality of the wafers until at least theprocessing of the wafer 200 is completed.

Film-forming Step S904

Thereafter, the film-forming step 5904 is performed by performing a step(A) and a step (B) sequentially.

Step (A)

In the step (A), as a sub-step (source gas supply step) S941 shown inFIG. 13, the HCDS gas is supplied to the wafer 200 in the processchamber 201. Specifically, the valve 330 b is opened to supply the HCDSgas into the gas supply pipe 310 b. A flow rate of the HCDS gas suppliedinto the gas supply pipe 310 b is adjusted by the MFC 320 b. The HCDSgas whose flow rate is adjusted is then supplied into the processchamber 201 through the nozzle 304 b, and is exhausted through theexhaust port 230. In the step (A), the N₂ gas serving as the inert gasis supplied to the wafer 200 in the process chamber 201 through thenozzles 304 a and 304 c on both sides of the nozzle 304 b. Specifically,the valves 330 d and 330 f are opened to supply the N₂ gas into the gassupply pipes 310 a and 310 c. A flow rate of the N₂ gas is adjusted bythe MFCs 320 d and 320 f, the N₂ gas whose flow rate is adjusted issupplied into the process chamber 201 through the nozzles 304 a and 304c, and is exhausted through the exhaust port 230. That is, in the step(A), the HCDS gas and the N₂ gas are supplied to the wafer 200.

For example, process conditions in the step (A) are exemplified asfollows:

Supply flow rate of the HCDS gas: 0.001 slm (Standard Liters Per Minute)to 2 slm, preferably, 0.01 slm to 1 slm;

Supply flow rate of the N₂ gas (per gas supply pipe): 0.5 slm to 5 slm;

Gas supply time (a time duration of supplying the HCDS gas and the N2gas): 0.1 second to 120 seconds, preferably, 1 second to 60 seconds;

Process temperature: 250° C. to 800° C., preferably, 400° C. to 700° C.;and

Process pressure: 1 Pa to 2,666 Pa, preferably, 67 Pa to 1,333 Pa.

By supplying the HCDS gas and the N₂ gas to the wafer 200 under theabove-described process conditions, for example, a silicon-containinglayer containing chlorine (Cl) is formed as a first layer on anoutermost surface of the wafer 200.

After the first layer is formed on the wafer 200, as a sub-step (sourcegas exhaust step) S942 shown in FIG. 13, the valve 330 b is closed tostop the supply of the HCDS gas into the process chamber 201. Then, theinner atmosphere of the process chamber 201 is vacuum-exhausted toremove the substances such as the gas remaining in the process chamber201. When the inner atmosphere of the process chamber 201 isvacuum-exhausted, with the valves 330 d through 330 f open, the N₂ gasis supplied into the process chamber 201 through the nozzles 304 a, 304b and 304 c. The N₂ gas supplied through the nozzles 304 a, 304 b and304 c serves as the purge gas. As a result, the inner atmosphere of theprocess chamber 201 is purged. In the sub-step S942, for example, eachflow rate of the N₂ gas supplied through each of the nozzles 304 a, 304b and 304 c is set within a range from 0.1 slm to 2 slm. The otherprocess conditions are the same as the process conditions in thesub-step S941 of the step (A) described above.

Instead of the HCDS gas, a chlorosilane source gas such asmonochlorosilane (SiH₃Cl, abbreviated as MCS) gas, dichlorosilane(SiH₂Cl₂, abbreviated as DCS) gas, trichlorosilane (SiHCl₃, abbreviatedas TCS) gas, tetrachlorosilane (SiCl₄, abbreviated as STC) gas, andoctachlorotrisilane (Si₃Cl₈, abbreviated as OCTS) may be used as thesource gas.

Instead of the N₂ gas, for example, a rare gas such as argon (Ar) gas,helium (He) gas, neon (Ne) gas and xenon (Xe) gas may be used as theinert gas. The same also applies to the step (B) described later.

Step (B)

After the step (A) is completed, as a sub-step (reactive gas supplystep) S943 shown in FIG. 13, the NH₃ gas is supplied to the wafer 200 inprocess chamber 201, that is, to the first layer formed on the wafer200. Specifically, the valves 330 a and 330 c are opened to supply theNH₃ gas into the gas supply pipes 310 a and 310 c. A flow rate of theNH₃ gas supplied into each of the gas supply pipes 310 a and 310 c isadjusted by the MFCs 320 a and 320 c. The NH₃ gas whose flow rate isadjusted is then supplied into the process chamber 201 through thenozzles 304 a and 304 c, and is exhausted through the exhaust port 230.Thereby, the NH₃ gas is supplied to the wafer 200. In the sub-step S943of the step (B), by opening at least one among the valves 330 d through330 f, the N₂ gas may be supplied into the process chamber 201 throughat least one among the nozzles 304 a, 304 b and 304 c.

For example, the process conditions in the step (B) are exemplified asfollows:

Supply flow rate of the NH₃ gas: 1 slm to 10 slm;

NH₃ gas supply time (a time duration of supplying the NH₃ gas): 0.1second to 120 seconds, preferably, 1 second to 60 seconds;

Supply flow rate of the N₂ gas (per gas supply pipe): 0 slm to 2 slm;and

Process pressure: 1 Pa to 4,000 Pa, preferably, 1 Pa to 3,000 Pa.

The other process conditions are the same as the process conditions inthe sub-step S941 of the step (A) described above.

By supplying the NH₃ gas to the wafer 200 under the above-describedprocess conditions, at least a part of the first layer formed on thewafer 200 is nitrided (modified). By modifying the first layer, a secondlayer containing silicon and nitrogen, that is, an SiN layer is formedon the wafer 200. When the second layer is formed, impurities such aschlorine contained in the first layer may form a gas phase substancecontaining at least chlorine during a modifying reaction of the firstlayer by the NH₃ gas, and the gas phase substance is discharged from theprocess chamber 201. As a result, the second layer becomes a layer whichcontains a smaller amount of the impurities such as chlorine than thefirst layer.

After the second layer is formed, as a sub-step (reactive gas exhauststep) S944 shown in FIG. 13, the valves 330 a and 330 c are closed tostop the supply of the NH₃ gas into the process chamber 201. Then, theinner atmosphere of the process chamber 201 is vacuum-exhausted toremove the substances such as the gas remaining in the process chamber201 according to the same process sequence and process conditions asthose of the sub-step S942 of the step (A).

Instead of the NH₃ gas, for example, a hydrogen nitride-based gas suchas diazene (N₂H₂) gas, hydrazine (N₂H₄) gas and N₃H₈ gas may be used asthe reactant.

Performing a Predetermined Number of Times

By performing a cycle wherein the step (A) and the step (B) areperformed non-simultaneously in this order a predetermined number (n, nis an integer equal to or greater than 1) of times, as a sub-step S945shown in FIG. 13, an SiN film of a predetermined composition and apredetermined thickness is formed on the wafer 200. It is preferablethat the cycle is performed a plurality of times. That is, the cycle isperformed (repeated) until a total thickness of the SiN film formed bystacking the second layer by performing the cycle a plurality of timesreaches the desired thickness under the condition that the second layerformed in each cycle is thinner than the desired thickness. In thepresent specification, the exemplary sequence of the film-formingprocess described above may be represented as follows:

(HCDS→NH₃)×n=>SiN

In the following descriptions, the same also applies to other examples.

Temperature Lowering Step S905 and Returning to Atmospheric PressureStep S906

After the film-forming step S904 is completed, a temperature adjustingoperation continued from the step S903 is also completed, and thetemperature of the wafer 200 in the process chamber 201 may be lowered(temperature lowering step S905). In addition, while lowering thetemperature of the wafer 200, the N₂ gas serving as the purge gas issupplied into the process chamber 201 through each of the nozzles 304 a,304 b and 304 c, and then the N₂ gas supplied into the process chamber201 is exhausted through the exhaust port 230. Thereby, the inneratmosphere of the process chamber 201 is purged with the N₂ gas, thusthe gas remaining in the process chamber 201 or reaction by-productsremaining in the process chamber 201 are removed from the processchamber 201 (after-purge). Thereafter, the inner atmosphere of theprocess chamber 201 is replaced with the inert gas, and the innerpressure of the process chamber 201 is returned to the atmosphericpressure.

Boat Unloading and Wafer Discharging Step S907

Thereafter, the seal cap 219 is lowered by the boat elevator 115 and thelower end opening of the manifold 226 is opened. The boat 217 with theplurality of processed wafers including the wafer 200 charged therein isunloaded out of the reaction tube 203 through the lower end opening ofthe manifold 226 (boat unloading). After the boat 217 is unloaded, thelower end opening of the manifold 226 is sealed by a shutter (not shown)through a seal such as an O-ring (shutter closing). Then, the pluralityof the processed wafers including the wafer 200 are discharged from theboat 217 (wafer discharging).

(3) Modified Examples

Subsequently, modified examples of the present embodiment will bedescribed with reference to FIGS. 5 through 7 and 14. These modifiedexamples may be arbitrarily combined. In addition, unless otherwisedescribed, configurations of the modified examples are similar to theconfiguration of the embodiment described above.

First Modified Example

As shown in FIG. 5, according to the present modified example, the threenozzles 304 a, 304 b and 304 c are provided in the gas supply area 222,and are configured to supply the two or more types of the gas into theprocess chamber 201. However, a shape of a gas supply port of the nozzle304 b configured to supply the source gas according to the presentmodified example is different from that of the nozzle 304 b according tothe embodiment described above.

A vertically elongated slit-shaped opening 332 b serving as the gassupply port configured to supply the gas is provided on the side surfaceof the nozzle 304 b. An upper end of the opening 332 b of the nozzle 304b is arranged lower than the lowermost dummy wafer among the dummywafers 200 b supported in the upper dummy wafer support region. Inaddition, a lower end of the opening 332 b of the nozzle 304 b isarranged higher than the uppermost dummy wafer among the dummy wafers200 b supported in the lower dummy wafer support region. That is, in thenozzle 304 b, the opening 332 b is provided in the product wafer supportregion, but is not provided in the upper dummy wafer support region andthe lower dummy wafer support region. With such a configuration, whenthe source gas is supplied in the step (A) of the film-forming stepdescribed above, the source gas is supplied to the wafer 200 in theprocess chamber 201 through the opening 332 b of the nozzle 304 b andthe inert gas is supplied through the gas supply holes 232 a and the gassupply holes 232 c of the nozzles 304 a and 304 c arranged on both sidesof the nozzle 304 b.

Second Modified Example

As shown in FIG. 6, according to the present modified example, threenozzles 404 a, 304 b and 404 c are provided in the gas supply area 222,and are configured to supply the two or more types of the gas into theprocess chamber 201. However, shapes of the nozzle 404 a and the nozzle404 c arranged on both sides of the nozzle 304 b configured to supplythe source gas according to the present modified example are differentfrom those of the nozzle 304 a and the nozzle 304 c according to thefirst modified example described above.

The nozzles 404 a, 304 b and 404 c are provided in the gas supply area222 from the lower portion toward the upper portion along thelongitudinal direction of the gas supply area 222 (vertical direction).The nozzle 304 b extends in the vertical direction along the boat 217accommodated in the process chamber 201, and is configured as anI-shaped long nozzle of a tube shape. Each of the nozzle 404 a and thenozzle 404 c is a multi-hole nozzle (porous nozzle), extends in thevertical direction along the boat 217 accommodated in the processchamber 201, and is configured as a U-shaped long nozzle of a tubeshape.

The nozzle 404 a is constituted by: an ascending pipe 404 a-1 connectedto the gas supply pipe 310 a such that the fluid can flow from the gassupply sources 360 a and 360 d to a lower end of the ascending pipe 404a-1 through the gas supply pipe 310 a; and a descending pipe 404 a-2connected to an upper end of the ascending pipe 404 a-1 such that thefluid can flow and provided substantially parallel to the ascending pipe404 a-1.

The nozzle 304 b is connected to the gas supply pipe 310 b such that thefluid can flow from the gas supply sources 360 b and 360 e to the lowerend of the nozzle 304 b through the gas supply pipe 310 b.

The nozzle 404 c is constituted by: an ascending pipe 404 c-1 connectedto the gas supply pipe 310 c such that the fluid can flow from the gassupply sources 360 c and 360 f to a lower end of the ascending pipe 404c-1 through the gas supply pipe 310 c; and a descending pipe 404 c-2connected to an upper end of the ascending pipe 404 c-1 such that thefluid can flow and provided substantially parallel to the ascending pipe404 c-1.

The gas supply holes 232 a and the gas supply holes 232 c are providedin the product wafer support region of the descending pipes 404 a-2 and404 c-2 on side surfaces of the nozzles 304 a and 304 c, respectively. Aplurality of gas supply holes (also simply referred to as “gas supplyholes”) 233 a and a plurality of gas supply holes (also simply referredto as “gas supply holes”) 233 c are provided in the upper dummy wafersupport region and the lower dummy wafer support region of the ascendingpipes 404 a-1 and 404 c-1 and in the upper dummy wafer support regionand the lower dummy wafer support region of the descending pipes 404 a-2and 404 c-2, respectively. The gas supply holes 232 a, the gas supplyholes 232 c, the gas supply holes 233 a and the gas supply holes 233 care continuously arranged at the same pitch as the distance between theplurality of the wafers including the wafer 200. An opening area of agas supply hole among the gas supply holes 233 a and 233 c may be setgreater than an opening area of a gas supply hole of the gas supplyholes 232 a and 232 c. That is, the number of the gas supply holes suchas the gas supply holes 233 a and the gas supply holes 233 c in thedummy wafer region (that is, the upper dummy wafer support region andthe lower dummy wafer support region) of the nozzles 404 a and 404 cconfigured to supply the inert gas may be more than the number of thegas supply holes such as the gas supply holes 232 a and the gas supplyholes 232 c of the nozzles 304 a and 304 c in the embodiment and thefirst modified example described above. As a result, it is possible tofurther lower a concentration of the silicon source in the dummy wafersupport region, and it is also possible to easily control the uniformityof the film thickness on the surface of the product wafer and theuniformity of the film thickness among the product wafers.

An upper end of an uppermost gas supply hole among the gas supply holes233 a of the nozzle 404 a and an upper end of an uppermost gas supplyhole among the gas supply holes 233 c of the nozzle 404 c are arrangedcorresponding to the uppermost dummy wafer among the dummy wafers 200 bsupported in the upper dummy wafer support region. In addition, a lowerend of a lowermost gas supply hole among the gas supply holes 233 a ofthe nozzle 404 a and a lower end of a lowermost gas supply hole amongthe gas supply holes 233 c of the nozzle 404 c are arrangedcorresponding to the lowermost dummy wafer among the dummy wafers 200 bsupported in the lower dummy wafer support region. With such aconfiguration, when the source gas is supplied in the step (A) of thefilm-forming step described above, the source gas is supplied to thewafer 200 in the process chamber 201 through the opening 332 b of thenozzle 304 b and the inert gas is supplied through the gas supply holes232 a, the gas supply holes 232 c, the gas supply holes 233 a and thegas supply holes 233 c of the nozzles 404 a and 404 c arranged on bothsides of the nozzle 304 b.

That is, the nozzles 404 a and 404 c are configured such that asubstantial opening area which is obtained by averaging along thelongitudinal direction the opening areas of the gas supply holes 233 aand 233 c arranged in the upper and the lower dummy wafer support regionis greater than another substantial opening area which is obtained byaveraging along the longitudinal direction the opening areas of the gassupply holes 232 a and 232 c arranged in the product wafer supportregion.

In addition, the nozzles 404 a and 404 c are configured such that anaverage opening width of each of the gas supply holes 232 a and the gassupply holes 232 c averaged in a nozzle longitudinal direction is 1% orless of a square root of a cross-sectional area of a flow path of eachof the nozzles 404 a and 404 c. According to the present modifiedexample, the average opening width averaged in the nozzle longitudinaldirection may also refer to an opening width of a continuous slit in thelongitudinal direction whose conductance is equal to a conductance perunit length in the longitudinal direction of the gas supply holes 232 aor the gas supply holes 232 c. In addition, the nozzle 304 b isconfigured such that an opening width of the opening 332 b of the nozzle304 b is 3% or more of a square root of a cross-sectional area of a flowpath of the nozzle 304 b. Instead of one continuous opening from theupper end thereof to the lower end thereof, the opening 332 b may beconfigured as a plurality of slits extending intermittently in thevertical direction and bridged on both sides thereof in order toincrease the strength thereof.

Third Modified Example

As shown in FIG. 7, according to the present modified example, the threenozzles 304 a, 304 b and 404 c are provided in the gas supply area 222,and are configured to supply the two or more types of the gas into theprocess chamber 201. However, the shape of the nozzle 404 c provided atthe side of the nozzle 304 b configured to supply the source gasaccording to the present modified example is different from that of thenozzle 304 c according to the first modified example described above.

The nozzles 304 a, 304 b and 404 c are provided in the gas supply area222 from the lower portion toward the upper portion along thelongitudinal direction of the gas supply area 222 (vertical direction).Each of the nozzles 304 a and 304 b extends in the vertical directionalong the boat 217 accommodated in the process chamber 201, and isconfigured as an I-shaped long nozzle of a tube shape. The nozzle 404 cextends in the vertical direction along the boat 217 accommodated in theprocess chamber 201, and is configured as a U-shaped long nozzle of atube shape.

The nozzle 304 a is connected to the gas supply pipe 310 a such that thefluid can flow from the gas supply sources 360 a and 360 d to the lowerend of the nozzle 304 a through the gas supply pipe 310 a.

The nozzle 304 b is connected to the gas supply pipe 310 b such that thefluid can flow from the gas supply sources 360 b and 360 e to the lowerend of the nozzle 304 b through the gas supply pipe 310 b.

The nozzle 404 c is constituted by: the ascending pipe 404 c-1 connectedto the gas supply pipe 310 c such that the fluid can flow from the gassupply sources 360 c and 360 f to the lower end of the ascending pipe404 c-1 through the gas supply pipe 310 c; and the descending pipe 404c-2 connected to the upper end of the ascending pipe 404 c-1 such thatthe fluid can flow and provided substantially parallel to the ascendingpipe 404 c-1.

The gas supply holes 232 c are provided in the product wafer supportregion, the upper dummy wafer support region and the lower dummy wafersupport region on a side surface of the descending pipe 404 c-2 of thenozzle 404 c. The gas supply holes 232 c are not provided in theascending pipe 404 c-1 of the nozzle 404 c.

By supplying the inert gas (purge gas) using the U-shaped (return shape)nozzle 404 c according to the present modified example, it is possibleto improve the quality of the film formed on the wafer 200. For example,the purge gas (N₂ gas), which is effective in improving the thicknessuniformity of the film, is often supplied at a large flow rate of 2 slmto 10 slm. The purge gas is supplied to wafers provided in the lowerportion of the boat 217 among the plurality of the wafers through theI-shaped nozzle before the purge gas is sufficiently warmed up. As aresult, a temperature of the purge gas may not be uniform from the lowerportion to an upper portion of the boat 217. However, by using theU-shaped nozzle 404 c, it is possible to sufficiently warm the purge gasbefore being supplied to the plurality of the wafers including the wafer200. As the temperature of the purge gas increases, a diffusion rate ofgas molecules also increases, and it is expected that it is possible toshorten an alternate supply interval of the source gas while maintainingthe quality of the film. In addition, a temperature at which the NH₃ gasbecomes a radical or a precursor is higher than a temperature at whichthe HCDS gas becomes a radical or a precursor. That is, it is demandedfor the NH₃ gas to become the precursor at a predetermined temperatureor higher, and it is preferable to maintain the NH₃ gas in the nozzlefor a sufficient time when lowering the process temperature to thepredetermined temperature. Preferably, by increasing a volume of thenozzle by using the U-shaped nozzle 404 c, it is possible to apply thenozzle 404 c to supply the reactive gas which is difficult to bedecomposed.

Fourth Modified Example

As shown in FIG. 14, according to the present modified example, incomparison with FIG. 1, the nozzles 304 a, 304 b and 304 c may bereplaced with nozzles 314 a, 314 b and 314 c, and the gas supply slits235 may be replaced with a vertical gas supply slit 315. The verticalgas supply slit 315 is an opening that is provided for each region ofthe gas supply area 222, and is configured to allow each region of thegas supply area 222 to fluidically communicate with the process chamber201. A width of the vertical gas supply slit 315 is substantially equalto a width of each region of the gas supply area 222 providedcorresponding to the vertical gas supply slit 315. Positions of an upperend and a lower end of the opening (that is, the vertical gas supplyslit 315) correspond to the upper end of the upper dummy wafer supportregion and the lower end of the lower dummy wafer support region,respectively. However, actually, the opening may be expanded to preventthe contact with the nozzles 314 a, 314 b and 314 c. The nozzles 314 a,314 b and 314 c extend vertically upward from the lower portion of thegas supply area 222, then extend obliquely upward toward a tube axis ofthe reaction tube 203, and then extend vertically again when reachingthe vertical gas supply slit 315. It is desirable that the nozzles 314a, 314 b and 314 c contact an inner peripheral surface of the reactiontube 203 without protruding from the vertical gas supply slit 315 towardan inner periphery of the reaction tube 203. When the nozzles 314 a, 314b and 314 c protrude toward the inner periphery of the reaction tube203, the nozzles 314 a, 314 b and 314 c may contact the boat 217 beingrotated. The gas supply port such as the gas supply holes 232 a, the gassupply holes 232 c, the opening 332 b, the gas supply holes 233 a andthe gas supply holes 233 c may be provided at the nozzles 314 a, 314 band 314 c, accordingly. According to the fourth modified example, thegas is efficiently supplied to each of the plurality of the wafers bydischarging the gas from positions closer to the plurality of thewafers. That is, a ratio of the gas discharged from a certain gas supplyhole reaching a wafer other than the corresponding wafer is reduced.Therefore, it is possible to improve the uniformity of the film amongthe plurality of the substrates.

OTHER EMBODIMENTS

While the technique of the present disclosure is described by way of theabove-described embodiment and the modified examples, theabove-described technique is not limited thereto. The above-describedtechnique may be modified in various ways without departing from thegist thereof.

For example, while the above-described embodiment and the modifiedexamples are described by way of an example in which the nitriding gassuch as the NH₃ gas is supplied through the two nozzles 304 a and 304 c,the above-described technique is not limited thereto. For example, thenitriding gas may be supplied through at least one among the nozzle 304a and the nozzle 304 c.

For example, while the above-described embodiment and the modifiedexamples are described by way of an example in which the gas supplyholes 232 b are provided only in the product wafer support region on theside surface of the nozzle 304 b configured to supply the source gas,the above-described technique is not limited thereto. For example, theabove-described technique may be preferably applied when the totalopening area of the gas supply holes 232 b or the opening 332 b providedin the dummy wafer support region on the side surface of the nozzle 304b is smaller than the total opening area of the gas supply holes 232 aand the gas supply holes 232 c provided on the side surfaces of thenozzles 304 a and 304 c configured to supply the inert gas and arrangedon both sides of the nozzle 304 b.

For example, while the above-described embodiment and the modifiedexamples are described by way of an example in which the gas supplyholes 232 b are provided only in the product wafer support region on theside surface of the nozzle 304 b configured to supply the source gas,the above-described technique is not limited thereto. For example, theabove-described technique may be preferably applied when the totalopening area of the gas supply holes 232 a and the gas supply holes 232c provided on the side surfaces of the nozzles 304 a and 304 cconfigured to supply the inert gas and arranged on both sides of thenozzle 304 b is larger than the total opening area of the gas supplyholes 232 b or the opening 332 b provided in the dummy wafer supportregion on the side surface of the nozzle 304 b.

For example, while the above-described embodiment and the modifiedexamples are described by way of an example in which the film containingsilicon as the main element is formed on the substrate (wafer), theabove-described technique is not limited thereto. For example, theabove-described technique may be preferably applied to form on thesubstrate a film containing a metalloid element such as germanium (Ge)and boron (B) as a main element other than silicon. In addition, theabove-described technique may be preferably applied to form on thesubstrate a film containing a metal element such as titanium (Ti),zirconium (Zr), hafnium (Hf), niobium (Nb), tantalum (Ta), molybdenum(Mo), tungsten (W), yttrium (Y), lanthanum (La), strontium (Sr) andaluminum (Al) as a main element.

For example, the above-described technique may be applied to form on thesubstrate films such as a titanium nitride film (TiN film), a titaniumoxynitride film (TiON film), a titanium aluminum carbonitride film(TiAlCN film), a titanium aluminum carbide film (TiAlC film), a titaniumcarbonitride film (TiCN film) and a titanium oxide film (TiO film). Forexample, gases such as titanium tetrachloride (TiCl₄) gas andtrimethylaluminum (Al(CH₃)₃, abbreviated as TMA) gas may be used whenforming the films described above.

(TiCl₄→NH₃)×n=>TiN

(TiCl₄→NH₃→O₂)×n=>TiON

(TiCl₄→TMA→NH₃)×n=>TiAlCN

(TiCl₄→TMA)×n=>TiAlC

(TiCl₄→TEA)×n=>TiCN

(TiCl₄→H₂O)×n=>TiO

The recipe used for the substrate processing may be separately prepareddepending on the contents of the substrate processing, and stored in thememory 121 c through an electrical telecommunication line or theexternal memory 123. When the substrate processing is started, the CPU121 a may select a proper recipe among a plurality of recipes stored inthe memory 121 c, depending on the contents of the substrate processing.Thus, it is possible to form plural kinds of films of variouscomposition ratios, qualities and thicknesses by only a single substrateprocessing apparatus in a universal and highly reproducible manner.Furthermore, it is possible to reduce the burden of an operator, and tostart the substrate processing promptly without an operation mistake.

The above-described recipes are not limited to newly created recipes.For example, an existing recipe which is already installed in thesubstrate processing apparatus may be changed to a new recipe. When arecipe is to be changed, the recipe may be installed in the substrateprocessing apparatus through an electrical communication line or arecording medium in which the recipe is written. The input/output device122 installed in the existing substrate processing apparatus may beoperated to directly change the existing recipe which is alreadyinstalled in the substrate processing apparatus to the new recipe.

The above-described embodiment and the modified examples may beappropriately combined. The process sequences and the process conditionsof the combinations may be substantially the same as those of theabove-described embodiment.

Films such as the SiN film formed in accordance with the above-describedembodiment or the modified examples may be widely used, for example, asan insulating film, a spacer film, a mask film, a charge storage filmand a stress control film. In recent years, as the semiconductor deviceis miniaturized, a thickness uniformity of the film formed on thesurface of the wafer is more strictly demanded. The above-describedtechnique capable of forming a film of a flat distribution on apatterned substrate with a high-density pattern formed thereon is veryuseful as a technique for responding to this demand.

EXAMPLES

Hereinafter, simulation results and evaluation results that support theeffects obtained in the embodiment and the modified examples describedabove will be described with reference to FIGS. 8 through 12.

According to a comparative example, the gases are supplied to theplurality of the wafers including the wafer 200 stacked in a multistagemanner on the boat 217 by using the three nozzles 304 a, 404 b and 404 cshown in FIG. 8A. Specifically, each of the flow rates of the N2 gassupplied through the nozzle 304 a and the nozzle 404 c is set to 100sccm, and the flow rate of the HCDS gas supplied through the nozzle 404b are set to 480 sccm. An opening 432 b configured to supply the HCDSgas are provided on the side surface of the nozzle 404 b in the upperdummy wafer support region, the product wafer support region and thelower dummy wafer support region.

According to an example of the present embodiment, the gases aresupplied to the plurality of the wafers including the wafer 200 stackedin a multistage manner on the boat 217 by using the three nozzles 304 a,304 b and 404 c shown in FIG. 8B according to the third modified exampledescribed above. Specifically, each of the flow rates of the N₂ gassupplied through the nozzle 304 a and the nozzle 404 c are set to 500sccm, and the flow rate of the HCDS gas supplied through the nozzle 304b are set to 480 sccm.

FIG. 9A schematically illustrates the simulation result showing aconcentration distribution of the silicon source in the process furnace202 when the nozzles according to the comparative example shown in FIG.8A are used, and FIG. 9B schematically illustrates the thicknessdistribution of the film on the surface of the product wafer and thethickness distribution of the film among the product wafers includingthe product wafer shown in FIG. 9A. FIG. 10A schematically illustratesthe simulation result showing a concentration distribution of thesilicon source in the process furnace 202 when the nozzles according tothe example of the embodiment shown in FIG. 8B are used, and FIG. 10Bschematically illustrates the thickness distribution of the film on thesurface of the product wafer and the thickness distribution of the filmamong the plurality of the product wafers including the product wafershown in FIG. 10A. The vertical axis shown in FIGS. 9B and 10Brepresents a partial pressure [Pa] of the silicon source. The horizontalaxis shown in FIGS. 9B and 10B represents a wafer number (wafer serialnumber) of the product wafers placed on the boat 217.

As shown in FIG. 9A, when the nozzles according to the comparativeexample are used, the opening 432 b is also provided in the upper dummywafer support region and the lower dummy wafer support region on theside surface of the nozzle 404 b configured to supply the source gas.Therefore, the source gas is uniformly supplied from the top to thebottom of the boat 217. However, since the dummy wafer supported in thedummy wafer support region is a flat wafer and the product wafer onwhich the pattern is formed is a structural wafer whose surface area islarge, the consumption of the source gas is different between the dummywafer and the product wafer. Therefore, the concentration (partialpressure) of the silicon source in the process chamber 201 is differentamong the upper dummy wafer support region, the lower dummy wafersupport region and the product wafer support region. In the upper dummywafer support region and the lower dummy wafer support region, theconcentration of the silicon source increases because the excess gas islarge. In the product wafer support region, the concentration of thesilicon source decreases. When a concentration difference of the siliconsource occurs in the process chamber 201, the concentration differencealso occurs even in the product wafer support region due to aconcentration diffusion. Specifically, the concentration (partialpressure) of the silicon source in a region in the product wafer supportregion in the vicinity of the upper dummy wafer support region or thelower dummy wafer support region may be different from the concentration(partial pressure) of the silicon source in a region far from the upperdummy wafer support region or the lower dummy wafer support region.Therefore, the uniformity of the film formed on the product wafer maydeteriorate.

In addition, as shown in FIG. 9B, when the nozzles according to thecomparative example are used, the partial pressure of the silicon sourcesupplied around the edge within the surface of the wafer is differentfrom the partial pressure of the silicon source supplied to the centerwithin the surface of the wafer. On the other hand, as shown in FIG.10B, it is confirmed that, when the nozzles according to the example ofthe embodiment are used, the uniformity on the surface of the wafer isdesirable.

In addition, as shown in FIG. 9B, when the nozzles according to thecomparative example are used, the partial pressure of the silicon sourcesupplied to the plurality of the wafers stacked in the height directionof the boat 217 varies depending on the position of each of theplurality of the wafers. On the other hand, as shown in FIG. 10B, it isconfirmed that, when the nozzles according to the example of theembodiment are used, the uniformity among the plurality of the wafers isdesirable. That is, according to the example of the embodiment, it ispossible to improve a uniformity of the concentration of the siliconsource supplied to the product wafer.

That is, when the nozzles according to the example of the embodiment areused, it is possible to uniformize the concentration of the siliconsource in the height direction of the plurality of the wafers stacked inthe boat 217 as compared with the case where the nozzles according tothe comparative example are used. In particular, it is confirmed that itis possible to reduce the concentration of the silicon source on theupper portion and the lower portion of the boat 217 and to improve theuniformity among the plurality of the wafers.

FIG. 11 schematically illustrates comparison results of thicknessdistributions of the SiN film on the surface of the product wafer whenthe SiN film is formed on the product wafer using the nozzles accordingto the comparative example and the nozzles according to the example ofthe embodiment. FIG. 12 schematically illustrates comparison results ofthickness distributions of the SiN film among the plurality of theproduct wafers when the SiN film is formed on the plurality of theproduct wafers using the nozzles according to the comparative exampleand the nozzles according to the example of the embodiment. The verticalaxis shown in FIG. 11 represents a wafer position. The horizontal axisshown in FIG. 11 represents the uniformity [%] on the surface of theproduct wafer. The vertical axis shown in FIG. 12 represents the waferposition. The horizontal axis shown in FIG. 12 represents the thickness[Å] of the SiN film formed on the product wafer.

As shown in FIG. 11, the uniformity of the film (SiN film) on thesurface of the product wafer is about 4.5% at a center portion (“CENTER”in FIG. 11) of the boat 217, about 7.5% at the lower portion (“BOTTOM”in FIG. 11) of the boat 217, and about 9.2% at the upper portion (“TOP”in FIG. 11) of the boat 217 when the film is formed using the nozzlesaccording to the comparative example. That is, the uniformity of thefilm on the surface of the product wafer varies greatly depending on theheight position of the product wafer. On the other hand, the uniformityof the film on the surface of the product wafer is about 4% when thefilm is formed using the nozzles according to the example of theembodiment. That is, the uniformity of the film on the surface of theproduct wafer shows almost no difference along the height direction ofthe boat 217.

In addition, as shown in FIG. 12, the uniformity of the film among theplurality of the wafers is about 7% when the film is formed using thenozzles according to the comparative example. On the other hand, it isconfirmed that, when the film is formed using the nozzles according tothe example of the embodiment, the uniformity of the film among theplurality of the wafers is about 2%. That is, the uniformity of the filmamong the plurality of the wafers is also desirable.

That is, as compared with the case when the nozzles according to thecomparative example are used, the uniformity of the film thickness amongthe product wafers stacked in the boat 217 is desirable from the lowerportion to the upper portion in the height direction of the boat 217when the nozzles according to the example of the embodiment are used,and it is possible to obtain a uniform film thickness among the productwafers stacked in a multistage manner in the boat 217 from the lowerportion to the upper portion of the boat 217 when the nozzles accordingto the example of the embodiment are used.

As described above, according to some embodiments in the presentdisclosure, it is possible to improve the uniformity of the film on thesurface of the substrate and the uniformity of the film among theplurality of the substrates including the substrate.

What is claimed is:
 1. A substrate processing apparatus comprising: asubstrate retainer configured to support a substrate; a process chamberconfigured to accommodate the substrate retainer, the process chambercomprising: an exhaust part configured to discharge a fluid in theprocess chamber to an outside thereof; and a supply part disposed at aposition different from a position of the discharge part and configuredto supply process gases capable of processing the substrate in theprocess chamber; a gas supply area configured to communicate with theprocess chamber through the supply part; a plurality of injectorsextending in an axial direction and arranged in the gas supply area in acircumferential direction and comprising: a first injector providedwith, on a side surface thereof, a plurality of first ejection holesconfigured to eject an inert gas flowing in the first injector into theprocess chamber through the supply part; a second injector providedwith, on a side surface thereof, a plurality of second ejection holes oran opening configured to eject a source gas, which is one of the processgases flowing in the second injector, into the process chamber through aplurality of second supply holes, wherein the source gas is thermallydecomposable; and a third injector provided with, on a side surfacethereof, a plurality of third ejection holes configured to eject areactant gas flowing in the third injector into the process chamberthrough a plurality of third supply holes, the third injector beingprovided such that the second injector is arranged between the firstinjector and the third injector; and a plurality of gas supply pipesthrough which the plurality of injectors communicate with a plurality ofgas supply sources, respectively, wherein the plurality of gas supplysources comprise the source gas, the reactant gas and the inert gas,wherein at least one of the source gas and the reactant gas comprises anelement constituting a film to be formed on the substrate.
 2. Thesubstrate processing apparatus of claim 1, further comprising: acontroller configured to be able to control a supply amount or a flowrate of the inert gas ejected through the plurality of third ejectionholes while controlling a supply amount or a flow rate of the source gasejected through the plurality of second ejection holes or the opening,wherein the second injector is arranged side by side with the firstinjector and the third injector.
 3. The substrate processing apparatusof claim 1, wherein the third injector is capable of purging or dilutingan excess of the source gas by ejecting the inert gas more through aplurality of ejection holes provided in at least one of an upper regionand a lower region in which no ejection hole of the second injector isprovided than in a middle region between the upper region and the lowerregion.
 4. The substrate processing apparatus of claim 1, wherein thefirst injector comprises two pipes at which the first ejection holes areprovided thereon and configured to eject the inert gas and the reactantgas, and wherein the third injector comprises two pipes at which thefirst ejection holes are provided thereon and configured to eject theinert gas and the reactant gas.
 5. The substrate processing apparatus ofclaim 1, wherein a first ratio of an opening width of the first ejectionholes averaged along a longitudinal direction to a square root of across-sectional area of a flow path of the first injector is less than asecond ratio of an opening width of the second ejection holes or theopening to a square root of a cross-sectional area of a flow path of thesecond injector.
 6. The substrate processing apparatus of claim 5,wherein the first ratio is 1% or less.
 7. The substrate processingapparatus of claim 5, wherein the second ratio is 3% or more.
 8. Thesubstrate processing apparatus of claim 2, wherein a substantial openingarea of at least one of the first ejection holes or the third ejectionholes obtained by averaging out those opening areas within an upperregion and a lower region is greater than a substantial opening area ofthe plurality of gas supply holes obtained by averaging out thoseopening areas within a middle region between the upper region and thelower region.
 9. The substrate processing apparatus of claim 2, whereinthe gas supply area comprises inner walls that divide an inner space ofthe gas supply area into three spaces in which the first injector, thesecond injector and the third injector are arranged respectively. 10.The substrate processing apparatus of claim 4, wherein the two pipes ofthe first injector comprise an ascending pipe connected to a respectiveone of the gas supply pipes and a descending pipe connected to an upperend of the respective ascending pipe, and wherein the two pipes of thethird injector comprise an ascending pipe connected to a respective oneof the gas supply pipes and a descending pipe connected to an upper endof the respective ascending pipe.
 11. The substrate processing apparatusof claim 10, wherein the two pipes of the first injector comprise afirst pipe having a part of the first ejection holes only within anupper region and a lower region of the first injector and a second pipehaving another part of the first ejection holes within the upper region,the lower region and a middle region of the first injector between theupper region and the lower region.
 12. The substrate processingapparatus of claim 11, wherein the first pipe of the first injector isarranged nearer to the second injector than the second pipe of the firstinjector, and wherein the first pipe of the third injector is arrangednearer to the second injector than the second pipe of the thirdinjector.
 13. The substrate processing apparatus of claim 1, wherein thesecond injector is able to eject the inert gas when the third injectorejects the reactant gas and eject the source gas when the third injectordoes not eject the reactant gas.
 14. A substrate processing apparatuscomprising: a substrate retainer comprising: a first substrate supportregion configured to support a first plurality of substrates; a secondsubstrate support region provided above the first substrate supportregion and configured to support a second plurality of substrates; and athird substrate support region provided below the first substratesupport region and configured to support a third plurality ofsubstrates; a process chamber in which the substrate retainer isaccommodated; a first gas supplier, a second gas supplier and a thirdgas supplier configured to supply gases into the process chamber andextending along the substrate retainer; and a plurality of gas supplyholes provided at each of the first gas supplier and the third gassupplier, wherein the first gas supplier, the second gas supplier andthe third gas supplier are provided in the same gas supply area, whereinthe plurality of gas supply holes of the first gas supplier are arrangedcorresponding to substrates supported in at least the second substratesupport region and are not arranged corresponding to substratessupported in the first substrate support region, wherein the pluralityof gas supply holes of the third gas supplier are arranged correspondingto substrates supported in at least the third substrate support regionand are not arranged corresponding to substrates supported in the firstsubstrate support region, and wherein the second gas supplier comprisesa gas supply port which is provided such that the gas supply port isarranged corresponding to substrates supported in at least the firstsubstrate support region.
 15. The substrate processing apparatus ofclaim 14, wherein the second substrate support region is a first dummywafer region, and the third substrate support region is a second dummywafer region.
 16. The substrate processing apparatus of claim 13,wherein the first gas supplier and the third gas supplier are dilutiongas suppliers and the second gas supplier is a source gas supplier. 17.A method of manufacturing a semiconductor device comprising: providingthe substrate processing apparatus of claim 1, and processing thesubstrate by performing: (a) ejecting the source gas into the processchamber through the second injector; and (b) ejecting the reactant gasinto the process chamber through the third injector.
 18. A method ofmanufacturing a semiconductor device comprising: providing the substrateprocessing apparatus of claim 14, and processing the substrate byperforming: (a) ejecting a source gas into the process chamber throughthe second gas supplier; and (b) ejecting a dilution gas into theprocess chamber through at least one of the first gas supplier and thethird gas supplier.
 19. A non-transitory tangible medium storing aprogram executable by a computer for performing the method of claim 17.20. A non-transitory tangible medium storing a program executable by acomputer for performing the method of claim 18.